Download electrical storms in patients with implantable cardioverter defibrillator

Bulletin of the Transilvania University of Braşov
Series VI: Medical Sciences • Vol. 7 (56) No. 2 - 2014
ELECTRICAL STORMS IN PATIENTS
WITH IMPLANTABLE CARDIOVERTER
DEFIBRILLATOR
D. TÎNT 1,2
C. BABA2
M.E. URSU2
S. MICU2
Abstract: Electrical storm is defined as the occurrence of three or more
distinct episodes of ventricular tachycardia or ventricular fibrillation in 24
hours, requiring the intervention of the defibrillator. The aim of the paper is
to present a case-series of patients with electrical storm requiring
hospitalization. The patients were collected from a retrospective study of 217
patients with ICD implanted at ICCO clinics between 01.02.200930.04.2014. We analysed retrospectively the patient’s files and the
recordings from ambulatory follow-up visits.
Key words: electrical storm, implantable cardioverter-deffibrilator,
ventricular tachycardia, ventricular fibrillation.
1. Introduction
3. Materials and Methods
Implantable defibrillators are lifesaving
and have improved mortality rates in
patients at risk of sudden death, both in
primary and secondary prevention.
However, these devices are unable to
modify the myocardial substrate, which
remains susceptible to life-threatening
ventricular arrhythmias.
Electrical storm (ES) is defined as the
occurrence of three or more distinct episodes
of ventricular tachycardia or ventricular
fibrillation in 24 hours, requiring the
intervention of the defibrillator [10].
We assessed the prevalence, features,
and predictors of ES in 217 patients with
ICD implanted at ICCO clinics between
01.02.2009-30.04.2014. We analysed
retrospectively the patient’s files and the
recordings from ambulatory follow-up
visits. Each patient was followed-up one
month after the implant and every three
months thereafter. The programmed
parameters were every time analysed and
changed if needed. At each interrogation
we also evaluated the number and type of
arrhythmia – related events (sustained/nonsustained ventricular tachycardia, number
of anti-tachycardia pacing therapies (ATP)
delivered, number and appropriateness of
shocks. We also have collected data
regarding the re-hospitalization. If the
patient was missing from follow-up visit,
2. Aim
To evaluate the characteristics, clinical
presentation and outcome of patients with
electrical storm requiring hospitalization.
1
2
Faculty of Medicine, “Transilvania” University, Brasov, Romania.
ICCO Clinics, Brasov, Romania.
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Bulletin of the Transilvania University of Braşov • Series VI • Vol. 7 (56) No. 2 - 2014
we made calls to find out the patient status
(hospitalized or death).
Implant indication was made according
to guidelines. Resynchronization therapy
(CRT-P) or resynchronization therapy with
defibrillator
support
(CRT-D)
was
recommended for reducing the morbidity
and mortality in patients with heart failure
NYHA III or ambulatory IV who had an left
ventricular ejection fraction (LVEF) ≤ 35%
and QRS ≥ 120 msec and for reduction of
morbidity and prevention of progression
disease in patients with NYHA II class
having (LVEF) ≤ 35% and QRS ≥ 120
msec [3], [4].
Cardioverter-defibrillator (CD) devices
were implanted for sudden cardiac prevention
in patients with LVEF ≤ 35% after
myocardial infarction and NYHA class II, III;
non-ischaemic cardiomyopathy (NICMP)
with LVEF ≤ 35% and NYHA class II and
III, in patients with LVEF 30-40% after
myocardial
infarction
and
positive
electrophysiological study and for secondary
prophylaxis in patients already experienced
an aborted cardiac death or severe sustained
ventricular tachycardia [10].
We selected for detailed presentation a
case-series of 6 patients with severe ES
which required hospitalization.
All the data were analysed with SPSS
software (version 13.0, SPSS Inc.,
Chicago. IL, USA).
4. Results
Most of the patients were men (190 p,
87.55%). The mean age of patients was
62.67+ 11.12 years (24-83). Seventy one
patients (32.71%) were hypertensive, 132
(60.82%) had dyslipidemia, 43 (19.81%)
were diabetics and 40 patients (32.71%)
were smokers.
Table 1
Summary table with patients hospitalized for electrical storm. CRT-D= cardiac
resynchronization therapy with defibrillator, SC-CD= single chamber cardioverterdefibrillator, DC-CD dual chamber cardioverter-defibrillator
No Gender Age Device
1
M
65
2
M
75
3
M
79
4
M
63
5
F
73
6
M
51
Etiology
for implant
CRT-D Non-Ischemic
cardiomyopathy
SC-CD Ischemic
cardiomyopathy
CRT-D Non-ischemic
cardiomyopathy
DC-CD Non-ischemic
cardiomyopathy
CRT-D Ischemic
cardiomyopathy
SC-CD Ischemic
cardiomyopathy
The defibrillator was implanted for
primary prevention of sudden cardiac
death in 170 patients (78.34%) and for
secondary prevention in 47 patients
(21.65%). According the type of the
Primary Time No.
Etiology for ES EF %
Prophy- to ES events
laxis (days)
yes
740
22 hypokalemia
25
yes
549
yes
307
no
490
no
620
no
1
>3
Beta-mimetics,
aminophylline
60 Pulmonary
thrombo-embolism
17 Pocket infection,
Endocarditis?
190 pneumonia
3
Ischemia?
15
25
50
20
35
device, 123 pts (56.68%) received a single
chamber defibrillator, 20 pts (9.21%) dual
chamber defibrillator and 73 pts (33.64%)
have received resynchronization therapy
with defibrillation support.
D. TÎNT et al.: Electrical Storms in Patients with implantable Cardioverter …
All patients were treated according to
current ESC guidelines [3]. Most of the
patients 213 (98.2%) received a betablocker, 167 patients (76.9%) received a
conversion enzyme inhibitor or angiotensin
receptor inhibitor and spironolactone was
administered in 169 patients (77.88%).
Only 14 patients (6.4%) were treated with
digoxin and 178 patients (82%) received a
loop diuretic.
Atrial fibrillation was present in 77
patients (35%) and 19 patients (8.7%) have
experienced at least one syncope before the
device implantation
ES requiring hospitalization was present
in 6 pts (2.76%). All patients survived the
severe events.
Since every case is particular we have
chosen to present each patient of these series.
CASE 1 – AF male, 65 years, known with
non-ischaemic cardiomyopathy with very
dilated LV (83/70 mm) severe LV
dysfunction (LVEF 22%), LBBB and
ambulatory NYHA IV heart failure. CRT-D
device (In Sync Sentry7298) was implanted.
This is a special implantable medical device
that has a complementary function apart
from CRT-D ones and uses thoracic
impedance to determine how much fluid is
present in the thorax, such as for detecting or
predicting congestive heart failure.
Two years later, after an episode of heart
failure decompensation self-treated with high
doses of loop diuretics (Furosemide 240
mg/day one month) he developed severe
hypokalaemia of 2.5 mmol/l followed by ES
consisted in many arrhythmic events, some
of them followed by syncope and/or shock.
Device interrogation revealed the presence of
22 arrhythmic events (10 VF and 12 FVT for
which more than one therapy was
attempted). The patient received in total 19
shocks in 24 hours for VT and had multiple
syncope. The charge time was > 16 seconds
for last events, which consist an indication
for device replacement. After the
normalization of potassium level and heart
135
failure decompensation treatment, a new
device (Lumax 300 HF-T) was implanted
with no other significant arrhythmic events
since last FUP.
CASE 2 – NC, 75 years, with diabetes
mellitus and dyslipidaemia, previous
myocardial infarction and surgical
revascularization. The patient
was
implanted with a single chamber ICD for
ischaemic cardiomyopathy with LV
dysfunction (LVEF of 35%). The CRT
criteria were not accomplished. Twenty
eight days after the implantation
procedure, the patient was re-admitted
presenting severe dyspnoea and pulmonary
oedema.
The
transthoracic
echocardiography revealed a severe LV
dysfunction with LVEF of 15%. On ECG
multiple episodes of VT with 150
beats/min. Device interrogation showed
multiple episodes of VT with 150-160
beats/min. The device has not performed
any intervention because the frequency of
VT was below the detection limit. The
therapy limits were 171 bpm for VT1, 200
bpm for VF and 231 bpm for fast VF.
The dyspnea was interpreted as bronchus
spasm and the patient was treated with
inhalator β-agonists and aminophylline
which probably triggered the ES.
Under intensive treatment of heart
failure, the outcome was good, with no
arrhythmic events thereafter.
CASE 3 – VZ, 79 years, no
cardiovascular risk factors, was implanted
with a CRT-D for non-ischemic dilated
cardiomyopathy. At the moment of
implantation, the LVEF was25% with a
very dilated LV (80/57 mm). Eight months
after the implantation, he has a surgery
procedure for gallstones. Nine days after
he was admitted in our clinic after he
received multiple shocks. At clinical
examination we found severe dyspnea and
left leg deep thrombosis suggesting.
Transthoracic echocardio-graphy showed
mild pulmonary hypertension and severe
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Bulletin of the Transilvania University of Braşov • Series VI • Vol. 7 (56) No. 2 - 2014
LV dysfunction (LVEF of 25%). A
thoracic CT scan confirmed pulmonary
thromboembolism. The outcome was
favourable under complex therapy,
including anticoagulant and amiodarone,
with no arrhythmic events thereafter.
CASE 4 - GA, 63 years with
cardiovascular risk factors (hypertension,
dyslipidemia, cigarette smoking). The
underline pathology was coronary artery
disease treated with PTCA with stent
implantation on ACX. He had no LV
dysfunction, but he experienced multiple
episodes of VT/VF after revascularization
therapy. The patient was implanted with a
dual chamber CD (Lumax 300 DR-T) for
secondary prophylaxis of SCD.
Eleven months after the device
implantation he came to ambulatory clinic
because he received a shock. Device
interrogation showed fracture of the
defibrillator lead. The lead was eventually
replaced and the defibrillation threshold
was tested. The procedure was complicated
with pocket hematoma. The pocket content
was evacuated, but after three days the
patient started to present chills and fever.
The pocket inspection showed deep
infection, thus the device was explanted.
Amethicillin resistant staphylococci was
isolated from the pocket and the infection
was treated with antibiotics after germ
sensibility was tested. After 7 days a sterile
system was re-implanted at the same part.
One month later the patient came again
with ES consisted in 17 arrhythmic events
(VT, VF) treated with ATP and 2 shocks.
Blood cultures were positive for methicillin
resistant staphylococci. The antibiotic
treatment was started. After one week of
surveillance, with no new arrhythmic
episodes, the patient was transferred in an
infectious disease department. After a very
long course of antibiotic treatment, the whole
system was explanted in a dedicated centre
and, another device was then implanted via
right subclavian vein.
CASE 5 - RG female, 73 years. In
February 2013 after the two episodes of
aborted sudden death due to ventricular
fibrillation, she was evaluated in our
department. At that time, ECG revealed
sinus rhythm with 70 beats/min., right
bundle branch block left posterior bundle
branch block and PR prolongation of 260
msec. Echocardiography showed systolic
dysfunction with a LVEF of 35 %. The
coronary angiography revealed significant
stenosis on mid left anterior descending
artery and thus, percutaneous angioplasty
with stent implantation (XIENCE PRIME
LL 3,5X33mm) was performed. According
to guidelines, CRT-D therapy was
indicated and a St Jude Medical
PROMOTETM Plus device was implanted.
We have tested the defibrillation threshold
and we found values under 20 J.
In November 2013 she was again
referred to our department after a long
hospitalization (30 days) for severe
pneumonia in an internal medicine
department. During this hospitalization,
she was in medical intensive care unit for
20 days. Antibiotic and general supportive
treatment was given, with resolution of
pneumonia, but deterioration of her
cardiovascular condition. During her stay
in internal medicine unit, continuous
cardiac monitoring was unfortunately not
possible, still serial ECG recordings were
performed as needed.
At admission in our clinic, the patient
was in a very severe condition, with heart
failure decompensation, class NYHA IV.
Echocardiography
showed
mitral
regurgitation grade III, severe systolic LV
dysfunction with LVEF of 20% and
pulmonary hypertension of 60 mm Hg.
The device interrogation showed EOL of
the device VVI resetting and the event
history was not available. The device was
eventually sent to headquarter producer St
Jude Medical. The device was interrogated
and has found to be in Backup VVI
D. TÎNT et al.: Electrical Storms in Patients with implantable Cardioverter …
(BVVI) mode. Analysis of the image
revealed the device charged 190 times in
approximately 90 minutes prior to the
device reset to BVVI mode.
After few more days of treatment, we
decided to replace the generator with a
new one and thus, a new PROMOTETM
Plus device was implanted uneventfully.
The outcome was favourable with no more
arrhythmic events.
CASE 6 – FA, male, 52 years, ischaemic
cardiomyopathy, old myocardial infarction
with no possible revascularization therapy.
He was evaluated after one symptomatic
sustained VT episode cardioverted with DC
shock. Echocardiography showed LV
dysfunction with LVEF of 35% and no
criteria for resynchronization therapy. A
single chamber CD was implanted. Next day
he presented 3 episodes of VT treated with
shock (1 episode) and ATP the other two
episodes. We have added amiodarone on top
of anti-ischaemic therapy. The patient was
discharged with no further events and
remained without arrhythmia after one month
follow-up.
5. Discussions
Electrical storm is an important, risk
factor for subsequent death among ICD
recipients, particularly in the first 3 months
after its occurrence [5].
Predictors of ES are: chronic heart
failure, secondary prophylaxis of SCD
(device implantation for VT, VF), low
LVEF (<25%), wide QRS (>120 msec),
use of digoxin, absence of beta-blocker
therapy, absence of revascularization
therapy after index arrhythmia, coronary
artery disease [1], [6], [8].
Apart from these factors, the common
triggers for ES are ischemia, electrolyte
disturbances, heart failure and some others
that remained unidentified.
The immediate consequence of an ES is
hospitalization, particularly in patients who
have received a shock from the device. Apart
from prognostic implications, electric
instability induces a status of anxiety with
137
psychological repercussion and may severely
affect patient’s quality of life [2].
A patient with ES has to be hospitalized
in an intensive care unit. The most urgent
evaluation concerns the hemodynamic
stability of the arrhythmias and, if they
degenerate into acute heart failure, prompt
assessment of the complications linked to
this (such as pulmonary edema or acute
renal insufficiency). Whenever a trigger is
identified, we have to take prompt
measures to correct it.
In case-series presented in this paper, in
one case (1) the trigger was hypokalemia
and after the correction of potassium level,
the outcome was good.
In two cases we have had an infectious
trigger (a pocket infection - case 4 and a
severe pneumonia – case 5). In the first case,
the infection was impossible to be overcome,
so the whole system had to be removed. In the
second case, the severe electrical storm led to
device exhaustion. After a complex treatment
and new device implanted, the outcome was
uneventfully for next six months.
An ischemic trigger was probable
present in case 6, unfortunately with no
revascularization solution. In this case
higher dose beta-blocker and amiodarone
were sufficient to limit the ES.
In case 3, general surgery was
complicated with pulmonary thromboembolism which probably led to
aggravation of heart failure and ES.
In case 1, 3 and 6 amiodarone was added
on top of standard therapy. In the absence
of contraindications (such as QT
lengthening or polymorphic ventricular
tachycardia), amiodarone is generally the
antiarrhythmic drug of choice and has been
validated in many clinical trials [7], [9].
6. Conclusions
Early detection and appropriate treatment
of every ES episode is very important
since ES represents an important,
independent marker for subsequent death
among ICD recipients, particularly in the
first 3 months after its occurrence [6].
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